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最近在搞一点小玩意，利用Arduino做电容按键的处理，按键用铜箔（2cm*2cm）贴在不透明的亚克力背面，焊接上导线连接到Arduino。
但出现的问题是，直接接触铜箔，数值可以大于2，但是经过亚克力以后，手触摸亚克力，数值只能2。增加到3个按键后，其他两个按键的值一直是2，第一个按键触摸后变为2，偶尔还会受到干扰，自己跳变。我知道直接触摸导线或铜箔数值会增大到十几，但还是想隔着亚克力进行操作。
希望高手们指教一下！
先附上参考代码：
[pre lang="arduino" line="1" file="Capacity"]int ledPin = 13;
int capval0,capval1,capval2;
void setup()
{
pinMode(ledPin, OUTPUT);
Serial.begin(9600);
Serial.println("Touch senser");
}
void loop ()
{
digitalWrite(ledPin,LOW);
capval0 = readCapacitivePin(8);
capval1 = readCapacitivePin(9);
capval2 = readCapacitivePin(10);
Serial.println("Touch senser");
Serial.println(capval0, DEC);
Serial.println(capval1, DEC);
Serial.println(capval2, DEC);
if (capval0 > 1) {
// turn LED on:
digitalWrite(ledPin, HIGH);
delay(10);
}
delay(300);
}
uint8_t readCapacitivePin(int pinToMeasure) {
// Variables used to translate from Arduino to AVR pin naming
volatile uint8_t* port;
volatile uint8_t* ddr;
volatile uint8_t* pin;
// Here we translate the input pin number from
// Arduino pin number to the AVR PORT, PIN, DDR,
// and which bit of those registers we care about.
byte bitmask;
port = portOutputRegister(digitalPinToPort(pinToMeasure));
ddr = portModeRegister(digitalPinToPort(pinToMeasure));
bitmask = digitalPinToBitMask(pinToMeasure);
pin = portInputRegister(digitalPinToPort(pinToMeasure));
// Discharge the pin first by setting it low and output
*port &= ~(bitmask);
*ddr |= bitmask;
//delay(1);
// Make the pin an input with the internal pull-up on
*ddr &= ~(bitmask);
*port |= bitmask;
// Now see how long the pin to get pulled up. This manual unrolling of the loop
// decreases the number of hardware cycles between each read of the pin,
// thus increasing sensitivity.
uint8_t cycles = 17;
if (*pin & bitmask) { cycles = 0;}
else if (*pin & bitmask) { cycles = 1;}
else if (*pin & bitmask) { cycles = 2;}
else if (*pin & bitmask) { cycles = 3;}
else if (*pin & bitmask) { cycles = 4;}
else if (*pin & bitmask) { cycles = 5;}
else if (*pin & bitmask) { cycles = 6;}
else if (*pin & bitmask) { cycles = 7;}
else if (*pin & bitmask) { cycles = 8;}
else if (*pin & bitmask) { cycles = 9;}
else if (*pin & bitmask) { cycles = 10;}
else if (*pin & bitmask) { cycles = 11;}
else if (*pin & bitmask) { cycles = 12;}
else if (*pin & bitmask) { cycles = 13;}
else if (*pin & bitmask) { cycles = 14;}
else if (*pin & bitmask) { cycles = 15;}
else if (*pin & bitmask) { cycles = 16;}
// Discharge the pin again by setting it low and output
// It's important to leave the pins low if you want to
// be able to touch more than 1 sensor at a time - if
// the sensor is left pulled high, when you touch
// two sensors, your body will transfer the charge between
// sensors.
*port &= ~(bitmask);
*ddr |= bitmask;
return cycles;
}[/code]
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发表于 2015-12-1 16:50:11
楼主
